Fifteen years ago, the music industry was still a high-functioning behemoth pulling in $38 billion a year at its peak, able to ignore the digital revolution that was about to denude it entirely. Starting in 1999, sales of recorded music fell an average of 8% a year; 2012 was the first time since then that sales went up — 0.3%. Last year, it reported $16.5 billion in global revenue. America accounted for $4.43 billion of that — approximately the same amount spent by AT&T, Chevy, McDonald’s, and Geico on ad buys in the U.S. alone.